Egg Albumen Proteins Research Articles

Effect of contact with male on the physical and chemical qualities of eggs of black harco layers

A group of 30 Black HARCO laying hers were reared together with 3 mature cocks, while another group were reared in an adjacent pen without cocks. Thus, while the first group of hens had full physical contact (including mating) with the males, the second group was restricted only to auditory and visual contacts with the males. Twelve eggs were selected at 2 - weekly interval within a 12 - week period from each group and chemically analyzed for total protein, cholesterol in the yolk were determined by colourimetric methods while the shell calcium concentration was determined by a litrumetric method. Egg yolk cholesterol was higher (P<0.05) in hens exposed to full physical contact with the males (16.78 vs 14.20 mg/ml) whereas egg yolk protein, albumen protein and egg shell calcium concentrations were not significantly different (P>0.05) between the 2 groups. Egg weight, egg components weights and hen day egg production were also lower in those hens exposed to full contact with the males. Physical contacts (including mating) between the cock and hen resulted in higher yolk cholesterol and lower physical qualities of eggs produced under such management system.

Research progress of protein-based memristor

Memristor, as a new type of electronic component that can realize high density, multi-function, low power consumption, and multi-level data storage, has brought significant changes to the field of circuit structure design, information storage theory, and artificial synapses simulation. In a wide range of memristors, the protein-based memristors have unparalleled natural advantages in other cutting-edge information technology fields such as implantable computing, human-computer interaction, and human-computer integration due to their controllable degradation, rich and cheap raw materials, and biocompatibility. Therefore, the memristor is considered as the most potential candidate for building the next generation of high-tech information electronic device. In this article, the latest research progress of protein based memristors is comprehensively reviewed. The research progress of other proteins, including the widely studied egg albumen and artificial recombinant protein with excellent performance are first summarized, and then the research process of silk fibroin-based memristors, the performance improvement of silk fibroin-based memristors brought by functional strategies are comprehensively introduced. The Structure-activity relationship between structure and performance of functionalized silk fibroin is analyzed. Finally, the performance of the protein-based memristor is comprehensively analyzed, and the future development opportunities of the green electronic device are also prospected.

Comparative study of herbal and non-herbal egg protein profiles using sodium dodecyl sulfate-polyacrylamide gel electrophoresis

Chicken egg yolk and albumen contain some bioactive proteins. The present study was conducted to compare the protein profile of yolk and albumen of herbal and non-herbal chicken egg. The herbals that supplemented into chicken feed consisted of turmeric, sambiloto leaves, soursop leaves, ginger and lemongrass. The protein profiles were measured in term of the numbers of bioactive peptide fraction and their molecular weight by SDS PAGE using descriptive qualitative analysis. The antioxidant binding protein were also evaluated. The result show that SDS-PAGE can separate the egg yolk protein fraction and albumen protein with molecular weight between 14-97 kDa. Egg yolk protein fraction of herbal eggs separated better than non-herbal eggs, whereas giving herbal to laying hens does not affect the number of fractions in albumen protein. Antioxidants from herbals were indicated binding the apoprotein and apolipoprotein of egg yolk, also avidin and ovalbumin of albumen. It can be concluded that herbals supplementation affects the bioactive protein fraction in chicken eggs.

Artificial and wearable albumen protein memristor arrays with integrated memory logic gate functionality

Ultra-flexible egg albumen protein paper with a permittivity of 15–21, which is an improvement of nearly 300% compared with native egg albumen, and the protein-based memristor arrays and photoelectric logic gates are developed.

The combined effect of formulation and pH on properties of polyethylene oxide composite fiber containing egg albumen protein

The aim of this work was to elucidate the influence of egg white albumen (EA) protein loaded on the electrospinning of PEO solutions under different concentrations and pHs conditions. Properties of the electrospun fiber mats, such as morphology, thermal properties, and wettability were analyzed. In addition, rheological behavior of the polymer solutions was measured to explain the electrospinnability for fiber formation. The rheological results showed that the addition of EA protein affects the molecular entanglement required to electrospin PEO, being able to incorporate up to 75wt% EA protein. The diameter of most of the PEO/EA fibers was in the range of 200–400nm. When comparing the effect of concentration and pH of the electrospinning solution, the morphology of the fibers was found to be mainly affected by the second one. FTIR analysis of the blend fibers confirmed the presence of the protein and revealed that the secondary structure changed with pH. From a thermodynamic point of view, the EA protein and PEO showed a high degree of mutual incompatibility. The presence of EA protein influenced PEO polymer thermal behavior, lowering its melting point and decreasing the quantity of PEO crystallites. All the PEO/EA electrospun fiber mats showed rapid water absorption, which increased as PEO concentration became higher, and similarly, when lowering protein concentration.

Effect of egg albumen protein addition on physicochemical properties and nanostructure of gelatin from fish skin.

The physicochemical properties and nanostructure of mixtures of egg albumen protein (EAP) and gelatin from under-utilised grass carp (Ctenopharyngodon idella) skins were studied. The gelatin with 1% EAP had an acceptable gel strength. The addition of 5% EAP significantly increased the melting and gelling temperatures of gelatin gels. Additionally, the colour turned white and the crystallinity was higher in gelatin gels with gradient concentrations of EAP (1, 3, and 5%). Gelatin with 5% EAP had the highest G' values while gelatin with 1% EAP had the lowest G' values. Atomic force microscopy showed the heterogeneous nanostructure of fish gelatin, and a simple coacervate with a homogeneous distribution was only observed with the addition of 1% EAP, indicating interaction between gelatin and EAP. These results showed that EAP effect fish gelatin's physicochemical and nanostructure properties and has potential applications in foods and pharmaceuticals.

Emulsification process controlled by a mixer type rheometer in O/W protein-based emulsions

In the present work, concentrated Oil-in-Water (O/W) emulsions were stabilized using egg albumen protein isolate as the only emulsifier. A helicoidal geometry was used and compared with a conventional one to assure an optimal emulsion preparation with that unusual geometry in order to come up with the utility of this rheometer as a valuable tool for understanding and controlling the emulsification process. The results put forward the importance of controlling the emulsification process to optimize the properties of the final emulsion and demonstrating a good agreement between in situ and off-line measurements obtained in mixer-type and conventional rheometers, respectively. Flow properties of the different emulsion prepared were measured, showing an increase in the viscosity with the agitation speed (from 10 to 16 to 114–117 Pa s), protein concentration (from 30 to 40 to 106–125 Pa s) and oil concentration (from 15 to 20 to 130–180 Pa s). Furthermore, the droplet size distribution (DSD) was also measured obtaining the influence of the different parameters with the Sauter diameter (a decrease from 20 to 30 to 7–8 μm, from 26 to 3 μm and from 17 to 24 to 8–14 μm was observed by increasing the agitation speed and the protein and oil concentration, respectively). The influence of the pH was also taken into account. Eventually, a relationship has been found that relates these properties to different composition (pH value, nature and concentration of proteins) or processing variables (agitation speed).

Endogenous contributions to egg protein formation in lesser scaup Aythya affinis

Lesser scaup Aythya affinis populations have declined throughout the North American continent for the last three decades. It has been hypothesized that the loss and degradation of staging habitats has resulted in reduced female body condition on the breeding grounds and a concomitant decline in productivity. We explored the importance of body (endogenous) reserves obtained prior to arrival on the breeding ground in egg protein formation in southwestern Montana during 2006–2008 using stable-carbon (δ13C) and nitrogen (δ15N) isotope analyses of scaup egg components, female tissue, and local prey items. From arrival on the breeding grounds through the egg-laying period, δ15N values of scaup red blood cells decreased while δ13C values became less variable; a pattern consistent with endogenous tissues equilibrating with local (freshwater) dietary sources. In 2006 and 2008, isotopic values for egg albumen and yolk protein indicated that most (>90%) protein used to produce these components was obtained on the breeding grounds. However, in 2007, a year with an exceptionally warm and dry spring, endogenous reserves contributed on average 41% of yolk and 29% of albumen. Results from this study suggest that female scaup can meet the protein needs of egg production largely from local dietary food sources. This highlights the importance of providing high-quality breeding habitats for scaup. Whether this pattern holds in areas with similar breeding season lengths but longer migration routes, such as those found in the western boreal forest, should be investigated.

Synthesis of Uniform TiO<SUB>2</SUB> Nanoparticles with Egg Albumen Proteins as Novel Biotemplate

A novel bio-templated route was reported for the fabrication of uniform and well dispersed TiO, nanoparticles using denatured egg albumen (EA) proteins network as template. Anatase TiO2 nanoparticles of ca. 9 nm with narrow size distribution were obtained under employed reaction conditions, as proved by the XRD and TEM results. The as-prepared TiO2 nanoparticles were further characterized by means of XPS, FTIR, TG-DTA and UV-Vis. Based on the characterization results, a possible process of heat-induced denatured protein network as template matrix to fabricate TiO2 nanoparticles was carefully proposed. The method with egg albumen as bio-template provides us a cheap, green and repeatable route for the fabrication of nanoparticles under mild conditions.

Estimations of repeatability and heritability of egg albumen antimicrobial activity and of lysozyme and ovotransferrin concentrations

1. The repeatability and heritability of growth inhibition by egg albumen of two major pathogenic bacteria, a Gram-negative (Salmonella Enteritidis) and a Gram-positive (Staphyloccocus aureus) and of two antimicrobial albumen proteins, lysozyme and ovotransferrin, were estimated in commercial pedigree hens. 2. Repeatability was evaluated in 100 egg-type hens at the beginning, middle and end of the laying cycle on eggs collected for 3 weeks. Heritabilities were estimated at 36 to 40 weeks of age on 400 pedigree hens (2 eggs/hen), which were the offspring of 25 sires each mated with 4 dams. Ovotransferrin and lysozyme were quantified by ELISA. Salmonella Enteritidis (S.E.) and Staphyloccocus aureus (S.A.) were inoculated into a sample of sterilised albumen and enumerated after incubation. 3. Total protein content in albumen decreased with age of laying hens, whereas there were increases in lysozyme or ovotransferrin concentrations and in the bacteriostatic effect of albumen. 4. Repeatability for bacterial growth in albumen ranged from 0·29 to 0·39 for the number of S.E. (log cfu/ml) one day post inoculation (p.i.) but was lower and more variable at 5 d p.i. or for S.A. number. It ranged from 0·27 to 0·38 for S.E. and S.A. number at the mid period of the laying cycle. Repeatabilities were low and variable for total egg albumen protein or lysozyme and ovotranferrin concentrations (0 to 0·22). 5. Negative phenotypic correlations were observed between lysozyme concentrations and S.E. number but that between lysozyme and S.A. number was not significant. 6. Heritabilities were low (0·01 to 0·09) for protein traits. They were 0·11 for S.A. number and 0·16 for S.E. number one day p.i. 7. It appears to be more efficient to select on global bacterial growth than on specific antimicrobial proteins. The most promising trait is the number of S.E. one day p.i.

The effect of instant green tea on the foaming and rheological properties of egg albumen proteins

AbstractThe effects of three varieties of instant green tea (from China, Japan and Kenya) on the foaming and thermal properties of 1% (w/v) egg albumen and the gelation properties of 5 and 15% (w/v) egg albumen were investigated. All varieties produced similar effects on the foaming and gelation properties of egg albumen, but to different extents depending on the tea constituents. Mixtures of 1% (w/v) egg albumen and 0.25–0.4% (w/v) instant green teas in distilled water showed the greatest foam expansion (800–1140%) and foam stability (97–100%) at 10 min after whipping compared with 1% (w/v) egg albumen alone (226% for foam expansion and 34% for foam stability). Addition of instant green teas at levels above 0.5% (w/v) decreased foam expansion and stability. Small‐deformation rheology of mixtures of 5% (w/v) egg albumen and 1 or 2% (w/v) instant green teas showed an initial increase in elastic modulus (G′) and viscous modulus (G″) followed by a small, broad peak, indicating that the binding of tea constituents (polyphenols) with proteins may be reversible between 20 and 54 °C; this peak was not seen for 5% (w/v) egg albumen on its own. Large‐deformation rheological tests also indicated increased strength of mixed egg albumen/green tea gels with increasing levels of instant green teas. Differential scanning calorimetry thermograms showed that for the same instant green tea a higher concentration decreased the onset and peak (Tm) temperatures and enthalpy change values of all egg albumen protein peaks. Copyright © 2007 Society of Chemical Industry

Influence of pH-Induced Unfolding and Refolding of Egg Albumen on Its Foaming Properties

ABSTRACT: The foaming properties of egg albumen, which had been subjected to low and high pH unfolding followed by refolding, were investigated. The foaming capacity of egg albumen, the stability of the foam, or both, could be improved by an unfolding and refolding regime by choosing proper unfolding and refolding pH values. The foaming capacities of egg albumen were greatly improved when the refolding was at pH 6.5, 7.5, or 8.5, whereas the foaming capacities could be either slightly increased or decreased when the refolding was at pH 4.5 or 5.5 compared with the controls. The foam stability was in almost all cases improved by the unfolding and refolding treatments except for a few cases of unfolding at pH 1.5 or 10.5. The foam stability and liquid drainage were improved most when the unfolding was at pH 12.5. Analysis of total and surface sulfhydryl groups, surface hydrophobicity, and protein analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) provided strong evidence that the partial unfolding of egg albumen proteins as well as the interactions among egg albumen proteins through disulfide and/or hydrophobic groups dictated the improvements in foaming properties. The increase in surface hydrophobicity showed better correlation with the improvement of foaming properties than the change of surface sulfhydryl content did.

Effect of Sucrose Addition and Heat Treatment on Egg Albumen Protein Gelation

ABSTRACT: Studies were conducted to evaluate the effect of sucrose (0% to 60% w/w) on the heat denaturation and gelation of egg albumen solutions (pH 7.0) by thermal analysis and rheological measurements. Temperature and frequency sweeps were carried out under small deformations to determine the temperature at which structure development began (Ts) and the storage modulus plateau (G0), respectively. The latter was used to estimate the molecular weight of the internal chains between cross-links (Mc) using the rubber elasticity theory. Gels were prepared under several heat intensities (70, 80, and 90°C/30 min), and the mechanical properties were determined under small (stress relaxation) and large (stress and strain at fracture) deformations. It was observed that increments in sucrose concentration could act in the stabilization of the proteins, promoting a significant increase in the onset values and temperature of denaturation. The gelling process showed aTs increase with higher sucrose concentration. Gelation and the gel mechanical properties and network density showed a strong dependence on sucrose concentration and heat treatment temperature. In a general way, the sucrose promoted an improvement in the gel network up to a determined value of sugar concentration. At higher sugar concentrations, the values for the rheological properties decreased, which could be related to an incomplete unfolding of the oval-bumin under these conditions.

Fish gelatin: Structure, gelling properties and interaction with egg albumen proteins

Gelatin was obtained from the skin of North Sea horse mackerel ( Trachurus trachurus), using sodium hydrogen carbonate (0.125%), sodium hydroxide (0.2%), sulphuric acid (0.2%), and citric acid (0.715%) in distilled water, followed by filtration, deionisation. The proximate composition of the extracted fish skin gelatin indicated that the ash, moisture, colour, weight average molecular weight (195.8 kDa), Bloom (230) and pH (6.0) compared well commercial gelatin. The imino acid and hydrophobic amino acids profile of extracted horse mackerel gelatin were closer to those of the commercial warm water tilapia gelatin rather than the non-gelling cod gelatin. FT-Raman spectroscopy confirmed that hydrophobic groups (tyrosine doublet ratio 850/830 cm −1 and CH stretch region) as well as alpha-helix and random coil, for horse mackerel gelatin were in between those of tilapia and cod gelatin. In addition, large and small deformation rheological and thermodynamic properties were investigated for horse mackerel gelatin in isolation and in combination with egg albumen (egg white) protein. A mixture of gelatin:egg albumen (3:10) gave greater G′ valuesthan expected. Both differential scanning calorimetry and microscopy supported interaction between gelatin and egg albumen proteins. The gelling properties and compatibility with egg proteins makes the horse mackerel gelatin a potential replacer of porcine and bovine gelatins in desserts and bakery products.

A comparative study of heat and high pressure induced gels of whey and egg albumen proteins and their binary mixtures

Large deformation rheological studies of either egg albumen or whey protein isolate (15% protein w/w) gels induced by heating at 90 °C for 30 min were compared to those induced by a range high pressures (400–800 MPa for 20 min). Gels made by heating indicated higher gel strength and Young's modulus values for whey protein from pressures of 400–600 MPa for 20 min but similar values at 650–800 MPa. In contrast, egg albumen showed no gelation below 500 MPa for 20 min, but there was an increase in both gel strength and Young's modulus with increasing pressure, although values remained lower than those of the heat-induced gels. A mixture of 10:5 whey/egg albumen showed the highest gel strength and Young's modulus for both heated and high pressure-treated (400–600 MPa) gels, although, the heated mixture had the highest values. Electron micrographs indicated that high pressure-treated gels had a porous aggregated network for egg albumen while whey proteins showed a continuous fine stranded network. The heated mixtures of whey:egg albumen (7.5:7.5) showed large dense aggregates whereas high pressure-treated mixtures produced smaller aggregates. Raman spectroscopy of both heated and high pressure-treated whey and egg albumen (15% w/w in D 2O pD7) and their binary mixtures (7.5:7.5, protein w/w) indicated changes in β-sheet structures in the Amide 111′ region (980–990 cm −1); however, peak intensity was reduced for high pressure-treated samples. β-Sheet structure (1238–1240 cm −1) present in heated whey was absent in high pressure-treated whey and in egg albumen. Involvement of hydrophobic regions was reflected by changes in the CH (1350 cm −1) and CH 2 (1450 cm −1) bending vibrations. In addition to the Trp residues at 760 cm −1, there were broad peaks at 874–880 cm −1 and tyrosine 1207 cm −1 in the high pressure-treated samples. Disulphide bands (500–540 cm −1) in heated whey and egg albumen proteins showed higher peak intensities compared to high pressure-treated samples. Differences in the experimental and theoretical spectra indicated changes in the hydrophobic regions, tyrosine (1207 cm −1) and tryptophan (880 cm −1) and CH 2 bending in high pressure-treated samples, whereas heated samples indicated marked changes in β-sheet structures (987 and 1238 cm −1) as well as hydrophobic regions CH (1350 cm −1) and CH 2 (1450 cm −1) bending vibrations.

Secretory proteins in the reproductive tract of the snapping turtle, Chelhydra serpentina

SDS-polyacrylamide gel electrophoresis was used to separate the secretory proteins produced by the epithelial and endometrial glands of the uterine tube and uterus in the snapping turtle Chelydra serpentina. The proteins were analyzed throughout the phases of the reproductive cycle from May to August, including preovulatory, ovulatory, postovulatory or luteal, and vitellogenic phases. The pattern of secretory proteins is quite uniform along the length of the uterine tube, and the same is true of the uterus, but the patterns for uterine tube and uterus are clearly different. We identify 13 major proteins in C. serpentina egg albumen. Bands co-migrating with 11 of these are found in the uterine tube, but at most 4 are found in the uterus, suggesting that the majority of the albumen proteins are most likely secreted in the uterine tube, not in the uterus. Although some of the egg albumen proteins are present in the uterine tube only at the time of ovulation, most of the bands corresponding to albumen proteins are present throughout the breeding season even though the snapping turtle is a monoclutch species. These results suggest that the glandular secretory phase in the uterine tube is active and quite homogeneous in function regardless of location or phase of the reproductive cycle.

Studies on egg albumen and whey protein interactions by FT-Raman spectroscopy and rheology

Large deformation rheological studies of either egg albumen or whey protein isolate (15% protein w/w) gels made by heating at 90 °C for 30 min indicated a higher gel strength and Young's modulus values for egg albumen compared to whey protein isolate. The proteins mixed in the ratio 10:5 whey/egg albumen indicated synergistic interactions producing greater than expected gel strength values. Small deformation rheological studies of egg albumen 15% (w/w) and whey protein isolate 15% (w/w) showed very low values of the storage modulus ( G′) at 20 °C suggesting that both proteins do not easily aggregate at room temperature. Whey proteins gelled at 80 °C, whereas egg albumen proteins were already cross-linked at 20 °C ( G′> G″). A mixture of 7.5% whey/7.5% egg albumen showed the highest G′ value at the end of both heating and cooling cycles but this value was lower than that of the individual proteins. Changes in the conformation, molecular structure and protein–protein interactions in whey and egg albumen (15% w/w in D 2O pD7.2) and their mixtures (7.5:7.5 protein w/w) were investigated by FT-Raman spectroscopy. Upon heating to 90 °C for 30 min, individual whey and egg albumen proteins showed changes in the CH (1350 cm −1), CH 2 (1450 cm −1) bending vibrations and Trp residues at 760 cm −1, reflecting involvement of hydrophobic interactions. Changes in the disulphide stretching vibrations were also observed. Peak intensity increased for β-sheet structures in the Amide 111′ region 980–990 cm −1 and decreased for helix structures (900–960 cm −1) for both egg albumen and whey proteins. Differences in the experimental and theoretical average spectra indicated changes in β-sheet structures, CH 2 bending, carboxyl and hydrophobic groups in heated binary mixtures of egg albumen and whey proteins, providing evidence of protein–protein interactions, observed by large deformation rheology.

Characterization of high-pressure-treated egg albumen.

Addition of NaCl or sucrose to egg albumen prior to high-pressure treatment (up to 10 min at 800 MPa) prevented insolubilization or gel formation after pressure treatment. As a consequence of protein unfolding, the treated albumen had increased viscosity but retained its foaming and heat-gelling properties. Susceptibility of egg albumen proteins to hydrolysis by trypsin increased dramatically after pressure treatment. The S-form of ovalbumin, the presence of which is an index of egg aging, was not found in any of the pressure-treated samples, which also did not display evidence for covalent protein aggregation. However, recognition of ovalbumin by an anti-ovalbumin antiserum was reduced to 40% of that of untreated sample.

Influence of pH on surface properties of aqueous egg albumen solutions in relation to foaming behaviour

The surface properties of aqueous egg albumen protein solutions (0.1 g litre−1) were studied at pH values of 4.8, 7.0, 9.2 and 10.7 and related to foaming behaviour such as bubble size distribution, overrun and drainage. By measurements far from equilibrium of dynamic steady state surface dilation using the overflowing cylinder technique, egg albumen showed ability to slow down surface expansion and to lower the dynamic surface tension. The pH-effect was small, but at pH 4.8 the film length, at which a motionless surface was created, was longer than at higher pH indicating a somewhat more rigid surface at low pH. Near equilibrium sinusoidal surface area deformation resulted in relatively high moduli of egg albumen, with a significant effect of pH. The surface modulus E showed at pH 4.8 an increase in the course of time, but at higher pH it was constant. Large deformation of egg albumen surface was not destructive, and for all pH values the surface behaved viscoelastic, with highest loss modulus E″ and tan θ values at pH 4.8. Surface deformation frequency sweeps revealed the relaxation processes to be relatively slow at pH 4.8 and faster at pH 7.0–10.7. Foamability measured as overrun of foam as a result of shaking and stirring was highest at pH 4.8 and lowest at pH 10.7. Foam stability against drainage was best at pH 7.0 after 30 min, but at a long-term scale foam at pH 4.8 was most resistant to drainage. Foam samples were subjected to microscopy and image analysis. The smallest bubbles were found at pH 4.8 (mean diameter 142 µm) and the largest at pH 7.0 (mean diameter 328 µm). In conclusion, the foaming behaviour of an aqueous egg albumen solution at pH 4.8 can be related to dynamic surface properties as follows: the more rigid behaviour of the surface at this pH favours a small bubble size and slow drainage of liquid from the foam. The high overrun at this pH can be explained by a lower dynamic surface tension, but also here film stability during foam making can be promoted by a more rigid liquid surface. © 1999 Society of Chemical Industry

Effect of ascorbic acid on the foaming and gelling of globular proteins

SummaryFoam expansion and foam stability of plasma and egg albumen proteins were enhanced in the presence of increasing concentrations of ascorbic acid (0.1–1.0%). BSA showed the greatest improvement in foaming properties following treatment with ascorbic acid, whilst foaming properties of egg albumen were improved to a limited extent. A combination of partial acid hydrolysis and treatment with 1% ascorbic acid was required to dramatically improve the foaming properties of bovine blood plasma. In the presence of sucrose, foam expansion of both native and ascorbic acid‐treated blood plasma was decreased. In contrast the foam expansion of ascorbic acid‐treated egg albumen was greater although this effect decreased slightly on incubation. the gelation of ascorbic acid treated proteins increased with increasing temperatures over 80–90°C, particularly for BSA and blood plasma, and with increasing concentrations of ascorbic acid. Ascorbic acid‐treated proteins exhibited enhanced surface and exposed hydrophobicity and reduced numbers of sulphydryl groups indicating the involvement of these factors in foam and gel formation.